1. Field of the Invention
The invention relates to a mouth switch assembly for mounting on a device and to be actuated by a user of the device with the user's mouth.
By use of a mouth switch, actuations of the device may be initiated with the mouth, which would otherwise be actuated perhaps by a hand switch, by a hand key or a foot switch. Using a mouth switch is advantageous in particular wherever the user has no hand free to carry out the desired actuation by hand.
In particular, the mouth switch assembly is intended for use on an optical device, in particular a microscope, and more particularly an operation microscope.
2. Brief Description of Related Art
A mouth switch assembly is known e.g. from published German patent application DE 102 32 688 A1, which is herewith incorporated in full by reference. The mouth switch assembly described therein is mounted on a microscope assembly comprising an operation microscope. The microscope assembly comprises a stand with joints hinged together, wherein the relative motion of the joints with respect to one another may be blocked or set free by suitable actuation of joint brakes. The mouth switch assembly arranged in the vicinity of an ocular lens of the operation microscope includes a pair of mouth pieces capable of being grasped by the teeth of a user, and a switch which is actuatable by biting and releasing the bite of the teeth grasping the pair of mouth pieces, wherein the switch is connected, via a controller, with the joint brakes. The joint brakes are configured to block the relative motion of the joints with respect to one another. Biting on the pair of mouth pieces results in setting free the joint brakes, so that the stand joints may be moved with respect to one another, and releasing the bite results in the joint brakes blocking again the movement of the stand joints with respect to one another. The user is thereby enabled to carry out his work, e.g. a surgical treatment, while observing the work field through the operation microscope. Whenever there is a need to change the view onto the work field or to view a different work field, the user bites on the pair of mouth pieces and thus enacts a release of the joint brakes. Then, the user can, while continuously viewing through the ocular and keeping both hands in the work field, change the position and/or orientation of the operation microscope by moving around in space as desired the mouth piece firmly held between his teeth. When the desired view of the work field is reached, the user releases the grip with his teeth on the pair of mouth pieces and enacts in this manner, that the joint brakes again block the motion of the stand joints with respect to one another, so that the new view onto the work field is fixed.
It has been found, however, that in the described use the user oftentimes does not manage to precisely fix the desired view of the work field. Subsequent repeated actuation of the mouth switch and re-positioning of the microscope is then necessary, which is tedious and cumbersome.